Turtonator first appeared in Setting the Trap! The group had heard rumours of a powerful Pokémon living on Blush Mountain, with Lewis determined to catch it. Meeting the group, Turtonator accepted Lewis' request for a battle.
Turtonator battled against four out of five of Lewis' Pokémon (with Wimpod immediately activating Wimp Out), using Shell Trap to deal massive damage whenever they got too close and Payback to return damage dealt to him. He was struck hard in the hole on its stomach by Vulpix's newly-learned Ice Beam, and was eventually defeated by Aipom's Gigavolt Havoc, which hit the same spot. Acknowledging Lewis' strength, Turtonator allowed the Trainer to catch him.
Turtonator was used as Lewis' first Pokémon in his Thrifty Megamart trial battle against the Totem Mimikyu. He made good use of his Shell Trap, although the move didn't seem to have much affect on the Disguise Pokémon. Despite managing to pull off a super-effective Payback, Mimikyu remained standing and defeated Turtonator with a Shadow Ball.
Turtonator was later used by Lewis to battle the Team Skull grunts occupying Po Town in A Team Skull Takeover! He used Shell Trap to keep the advancing Pokémon away, but soon became overwhelmed and was saved by Nanu's Krookodile.
Turtonator was used in Lewis' Grand Trial battle against Nanu in Night Out with Nanu! He battled against Nanu's Krookodile and managed to defeat it with Dragon Pulse after a long battle. Turtonator then faced off against Nanu's Alolan Persian, though the damage he had taken from Krookodile meant he was unable to stand up to Persian's Night Slash and was defeated.
In Revenge - Best Served Hot!, Turtonator was sent out to battle Persian once again. This time, he took Persian's attacks with ease and fought back with Dragon Pulse. However, Persian went for a Black Hole Eclipse, dealing major damage to Turtonator. On the brink of fainting, Turtonator heard Lewis' encouragement and showed its full fighting spirit, its internal flame burning so hot it made Turtonator glow. Using this, Lewis had Turtonator use Inferno Overdrive, knocking out Persian and giving Lewis the win.
Turtonator is proven to be an incredibly powerful Pokémon, being able to defeat almost the entirety of Lewis' team without much trouble. It is seen on occasion that Turtonator sometimes doesn't realise his own strength, accidentally burning Lewis with Fire Blast when it is happy. Turtonator is also a bit of a glutton, eating a vast amount of food in a very quick time.
Turtonator was shown to love battling and developed a rivalry with Nanu's Alolan Persian after seeing its strength, becoming determined to get revenge after it had defeated him. This shows that Turtonator does have a dark side.